This invention relates generally to an electrostatographic printer and copier, and more particularly, a cleaner with a changing bias to monitor cleaning performance and to predict cleaner life.
Brush cleaners operate by removing the toner from the photoreceptor both with mechanical and/or electrostatic forces. The fibers on the brush touch the untransferred toner and the toner is removed from the photoreceptor onto the brush. The toner on the brush is then transported to a detoning device (e.g. flicker bar, detoning roll, air system, combs, etc.) removing the toner from the brush (i.e. detoned). An electrostatic brush cleaner removes the toner primarily with electrostatic forces. For a dual electrostatic brush cleaner, negative toner is removed with a positively biased brush and positive toner is removed with a negatively biased brush. Dual electrostatic brush cleaners are used in high volume full color single pass 101 (Image on Image) printers.
Unreliable predictions of cleaning performance failure in a cleaning system causes down time and customer dissatisfaction. A highly reliable method or apparatus of predicting cleaner performance is needed, especially in high volume full color single pass 101 printers. Down time could be minimized by the ability to accurately predict cleaner brush life.
The following disclosures may be relevant to various aspects of the present invention and may be briefly summarized as follows:
U.S. Pat. No. 5,546,177 to Thayer discloses a method and apparatus for monitoring the performance of a cleaner brush used to clean a photoreceptive surface. The apparatus and method include developing a toner patch of known first length on the imaging surface and then removing that toner patch from the imaging surface using a cleaner brush that accumulates a toner patch of a second length on the surface of the brush. The comparison of the toner patch on the imaging surface versus the toner patch on the brush surface monitor the cleaning efficiency of the cleaner brush.
U.S. Pat. No. 5,153,658 to Lundy et at. discloses a process for controlling the amount of film buildup on a photoreceptor surface caused by certain print mode and/or material throughput conditions in a single pass highlight color printer which enables or promotes photoreceptor filming by the DAD toner additive (i.e. zinc stearate). Such filming results in the tri-level Image Push defect. This process utilizes toner coated cleaner brushes to control the film buildup thus preventing the defect. This process defines a functional equation that maintains a toner concentration at the cleaner brush fiber tips thereby controlling photoreceptor filming.
U.S. Pat. No. 5,119,132 to Butler discloses an invention that relates generally to an electrographic apparatus and more specifically to an improved structural arrangement in electrographic apparatus of the type having a densitometer, which arrangement achieves improved measuring of marking particle density on a photoreceptor or the like. Wherein, use of a charge-coupled device (CCD) allows for a pixel-by-pixel recordation of the photo intensity reflected off of the photoreceptor and toner test patch. Therefore, as a result of the increased sensitivity of the toner measuring, it is possible to measure denser patches of toner, both black as well as color. Thus, allowing for accurate monitoring of the mount of toner capable of being placed onto a photoreceptor.